Cassius

I recently got a 1990 Cannondale 3.0 Criterium for free (!), it had been siting unused for several years and the owner hade planned to throw it away. I already have a bike that works flawlessly (an old Aelle frame with modern 22 speed components) so I thought I'd just have "fun" with this one

It came with Dura Ace 7400 series hubs (on campagnolo tub rims), 7400 BB, 600 crank and front derailleur, indexed DT Dura Ace shifters, 7402 Dura Ace rear derailleur, 105 (1055) brakes and levers, 600 seat post, 3T Superlegerro drop bars and 3T Record AR stem. The frame was red so over the years parts have been swaped (I can't find a red version from 1990 och 1989 that has Dura Ace equipment).

First of all I wanted brifters, and found a set on ebay which included the DT cable stops And and extra rear derailleur. Since I have two I thought it Might be fun to see if I could rebuild one of them to make a lightweight version.

But.. Question 1: Does anyone have a tip on how to remove the pressed pins holding the body togheter?

Question 2: The derailleur cage, does anyone know if this is intercahngable with anything from a never series? Some of the newer series have aftermarket carbon cages available, but none list the 740s as compatible. But I doubt any of the manufacturers have checked compatability for that series..

noodle soup

You might want to have this thread moved to the Mechanics forum.

Why are you looking to swap the derailleur cage, and what do you hope to accomplish?

datlas 

I would do my homework on whether the brifters you chose are compatible with that old RD. You may do better just getting a modern RD. I am guessing you want a longer cage to allow wider gear range, which is a headache in itself and again, may be best solved with a modern 105 RD.

noodle soup

when you say “modern 105 RD” that’s not entirely accurate. An 11spd RD won’t work with those shifters, but a 10spd one(5600, 5700) will work fine.

Remember that a long cage rear derailleur won’t allow you to use a huge cassette(bigger than 28t or maybe 30t max)

If the OP wants to use a large cassette, a Wolftooth Road Link will help.

datlas 

We don't even know what brifters he got. Do we?? If they are 7400 series then yes he is kinda stuck with the old RD. There is a shimano compatibility chart somewhere that can be helpful.

noodle soup

i assume he has 8spd DA shifters, but he never stated that.

if he has 8spd shifters, he can use any 8/9/10spd Shimano road derailleur.

Dave Mayer

Big assumption: that the OP has 8-speed Dura-Ace shifters. If so, then only a 740X series rear derailleur will index correctly with the Dura-Ace shifters (downtube or brifters).

Installing a different 7/8/9/10 speed Shimano rear derailleur will cause undershift - i.e. - the derailleur will not travel far enough to line up with the cogs in the cassette.

As far as swapping another derailleur 'cage' on to the existing Dura-Ace unit... I have disassembled and hybridized about every type of Shimano derailleur out there, and I cannot see how installing another cage can work; 7/8 speed Dura-Ace is very unique kit.

Since 7/8 speed Dura-Ace rear derailleurs had a tiny chain wrap capacity, and the ability to handle a 26 tooth cog (max), I assume the OP wants lower gearing. About the only suggestion I can make here is install a Suntour Accushift RD from their mountain bike lineup - such as Suntour XC Accushift. A strange coincidence is that Accushift rear derailleurs have about the same actuation ratio as Dura-Ace 740X. I once installed a Suntour XC Comp rear derailleur on an otherwise Dura-Ace 8-speed drivetrain, and it shifted like butter. Allowed me to install a 30-tooth cog at the back - for lower gearing.

Dave Mayer

Thanks for the quote, but your response is completely wrong. 8speed Dura-Ace needs a rear derailleur with an actuation ratio of 1.8:1.. All other 7/8/9/10 speed Shimano road (and most MTB) rear derailleurs have an actuation ratio of 1.67:1.

noodle soup

Has the OP ever said what shifters he has?

I still want to know what he is trying to accomplish with the cage swap.

Cassius

I see that I should have been more clear on what parts I have and my plan..

I'm sticking to the 8 speed configuration, and since the Dura Ace stuff are unique I also got the 8 speed Dura Ace brifters. For the front derailleur I haven't found any incompatible info with the Dura Ace brifters? (Haven't sourced a Dura Ace front derailleur, thought I'd stick to what I have if it works).

The cage then.. Well, I'd like to use larger jockey wheels if I can, a longer cage would make that easier. There are a number of different complete kit's with larger sprockets and carbon plate cages. By pure visual looks the ones for the 6800 series Ultegra derailleurs could work so I've started to look for a cheap worn bit of those to see if it might work. The other bike I have has the 8000 series Ultegra at the rear so not the same construction.

Gearing then. I had planned to get one 12-23 and one 11-28 cassete and mix those to get an 11-19 or 12-20 corncob. So it's not for bigger cogs in the rear

And the goal, lightweight. As previously stated this is more for the fun of it, I have two 7402 RD's so one will be lightened as much as I dare, I have contacts that could provide me with aluminium pivot bolts and cage bolts wich will do most of the weight gains. The jockey wheels arent heavy, but would still weigh more than a set of skeleton wheels. I haven't found any cheap ones that are below 11g yet (in 10T size) but 11T I've found some that are 6g. I've also found 14T that are below 10g. This would all be theoretical but once more, as stated, it's mostly for fun

I got the pins out atleast (well three of them, the last one will be difficult). And I guess I Could cut of the part of the cage that attaches to the derailleur and epoxy on a carbon plate instead. But it would just be easier If I could source a lighter cage that fits directly

The bike will also get carbon wheels with straight pull Novatec hubs in 38 and 50mm height (28mm outer width, U shaped tubs and then 25mm tires), a carbon dropbar with integrated stem, most likely a Columbus minimal fork, carbon seatpost, Campy brakes with Ti bolts that should be under 300g for the pair and a Dura Ace 7410 crank with a Ti BB. Weight goal is sub 8kg. The brifters are kinda heavy aswell so they will likely also get the dremel treatment. Just need to make a special tool first

masi61

You might just need to purchase the oversized pulley aftermarket cage/pulley assembly you are interested in and try it. I have seen where Shimano mountain cages have been transplanted onto a Dura Ace 7402 RD so I can’t think of why something like the KCNC one wouldn’t work.

Could you provide a picture of the loose pins you are referring to?

Cassius

On this pic you can see four pins that hold the four parts of the RD body together: https://www.oldbici.it/wp-content/upl...ldbici-2-1.jpg

Three of these I have grinded off enough to hammer them out from the back (the back isn't visible). The fourth ends up behind the plate axle spring housing. I haven't tried to grind out the back of that one yet..

I guess, the chinese knock offs aren't that expensive. Still, buying stuff for 50€ I don't need feels like a waste.. I'm not in a hurry so I'll keep an eye out Would also be interesting if a Ti spring could fit the bill.. Atleast the Shimano RD's seem to have two different setups (when talking about road RD's) that buy pure visuals looks to be the same from the 8 spd DA until today. Campy springs also look the same but don't know if the diameters will match..

datlas 

It may be kinda late into the process, but unless you feel strongly about oversized pulleys I would suggest you stick with what you have.

Kimmo 

There are at least two or three different methods Shimano have used to attach the cages to road RDs over the years. Best move is to pull it off and see if it's compatible with a later derailer (by pulling off the other cage too).

seypat

You could ride with 1 water bottle and fill it up more often. That would be more of a weight reduction than you will get from what you are doing.

noodle soup

+1

Unless the OP is losing TTs by a second or two, he'll gain nothing by this modification.

masi61

Here is a 7800 10-speed series rear derailleur that I just retrofitted with the KCNC red anodized pulley/black ano cage modification finally completed:

masi61

I purchased the cage for the purpose of repairing a used 7800 RD that had a damaged cage. The pin that prevents the partly wound up spring from unwinding, had sheared off. So I hope to use this on this Klein Quantum and these older Dura Ace 7850 tubeless clincher wheels I’m trying to return to service.

It seems like the bigger pulleys maybe might act kind of like a “GS” mid-cage version and work a bit better with a wider range rear cassette. I have an 11-28 Ultegra CS-6700 10-speed cassette that I plan to run with an Ultegra 6600 traditional road double crank with 53/39 chainrings. I think the set-up should be versatile and classy. I would also expect the 2 x 10 STI shifting to be spot on with my used 7800 STI shifters.

Just giving this as an example of taking older series Dura Ace and Ultegra parts and installing them on an everyday road bike. The pin on the cage that stops the rotation of the cage spring is easy to install as was transferring the original 7800 cage bolt onto the new KCNC cage. The 2 lightweight bolts provided were for 6800 Ultegra and 9000 Dura Ace. Each bolt was a little different and not an exact match so I just stuck with the original bolt and noted all the little parts: a nylon seal, and a little aluminum sleeve that slides behind the spring.

For your 7402, you could just remove your pulleys, then the outer cage, then just loosen the bolt for the inner cage and carefully release the spring tension to get the inner cage off and spring out. Then you can look at the mechanism and perhaps compare it to a long cage RD from the same era as your 7402 (1990?). The KCNC one I have has holes drilled in multiple locations to permit alternate mountings of the spring. This makes it workable outside of the narrow 6800/9000 specification it is sold under. I’m about to finish this Klein and will be test riding it soon so I can post back here an update about his RD setup. The oversized red pulleys give a sophisticated look and the bearings are very smooth in the pulleys. I run a 2 chain, waxed rotation so my drivetrains stay clean BTW.

masi61

Just a bit confused how the spring and pins could be so worn out. These derailleurs have tight tolerances with the slant parallelogram rivets are very strong spring action. How does one wear out an 8 speed Dura Ace rear derailleur? All that I’ve encountered in the wild are stiff and precise, just sometimes having varying levels of road rash cosmetically but not functional.

Cassius

seypat and noodle soup: First of all, I'm not planning on having any waterbottl on this bike. Second of all, I don't race. Only cycle for fun and workout/commuting. Third of all, did you not read that I'm doing this for the pure fun of it? Fourth of all, how does your replies contribute to this thread?

Masi: The pins aren't worn out, I wanted them out in order to work with the body more easily. I've started to grind away material from one of the parts (got the fourth pin out this morning so the RD is now completly disassembled). I'll continue, once finished with the first, with the remaining three. Then sand it down and paint it and put it back together hopefully a bit lighter then when I started Grinding away on the body probably won't save any more then 10-20g, but since these weigh roughly 200g from the beginning that's 5-10%. New bolts and wheels, maybe a lighter cage, might bring it down below 150g which is a 25% weight saving
It would be interesting to hear how the KCNC cage works for you

Regarding jockey wheel size, I just have an open mind. The carbon cages that are cheap usually have bigger wheels, smaler wheels (like the 11T 6g versions I know of) are however lighter and closer to "stock" so we'll see what I end up with

Just in case anyone has managed to miss it. This is only for fun, I'm not chasing fractions of a second during races (since I don't race, if I raced I would have bought a better suited bike to begin with), this is mainly to take my mind away from work for a little while every now and then. Those here that have jobs that be stressful (I'm in construction site management) probably understand quite well what half an hour of completly non work related thoughts can do for overall calmness

Kimmo 

Here's a tip - stay away from aluminum pulleys; they're noisy. You can find resin BB pulleys on eBay in all sorts of tooth counts, even narrow/wide for even numbers.

I squeezed 12t/14t into the standard cage on my Red RD.